Cpr chest compression system with dynamic parameters based on physiological feedback

ABSTRACT

A CPR system includes a retention structure to retain the patient&#39;s body, and a compression mechanism to perform CPR compressions to the patient&#39;s chest. The CPR system further includes a processor to control the compression mechanism, and thus the performance of the CPR compressions. In embodiments, the CPR system compresses at a rate or frequency that is varied based on feedback gathered from physiological sensors that detect physiological characteristics of the patient during treatment.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 15/298,198, filed Oct. 19, 2016, which claims priority fromU.S. Provisional Patent Application Ser. No. 62/243,613, filed on Oct.19, 2015, and also from U.S. Provisional Patent Application Ser. No.62/243,617, filed on Oct. 19, 2015, and also from U.S. ProvisionalPatent Application Ser. No. 62/243,620, filed on Oct. 19, 2015, and alsofrom U.S. Provisional Patent Application Ser. No. 62/243,547, filed onOct. 19, 2015, the disclosures of all of which, as initially made, arehereby incorporated by reference.

BACKGROUND

In certain types of medical emergencies a patient's heart stops working,which stops the blood from flowing. Without the blood flowing, organslike the brain will start becoming damaged, and the patient will soondie. Cardiopulmonary resuscitation (CPR) can forestall these risks. CPRincludes performing repeated chest compressions to the chest of thepatient, so as to cause the patient's blood to circulate some. CPR alsoincludes delivering rescue breaths to the patient, so as to create aircirculation in the lungs. CPR is intended to merely forestall organdamage and death, until a more definitive treatment is made available.Defibrillation is one such a definitive treatment: it is an electricshock delivered deliberately to the patient's heart, in the hope ofrestoring the heart rhythm.

Traditionally, CPR has been performed manually. A number of people havebeen trained in CPR, including some who are not in the medicalprofessions, just in case they are bystanders in a medical emergencyevent.

Manual CPR may be ineffective, however. Indeed, the rescuer might not beable to recall their training, especially under the stress of themoment. And even the best trained rescuer can become fatigued fromperforming the chest compressions for a long time, at which point theirperformance may become degraded. In the end, chest compressions that arenot frequent enough, not deep enough, or not followed by a full releasemay fail to maintain the blood circulation required to forestall organdamage and death.

The risk of ineffective chest compressions has been addressed with CPRchest compression machines. Such machines have been known by a number ofnames, for example CPR chest compression machines, CPR machines,mechanical CPR devices, cardiac compressors, CPR devices, CPR systems,and so on.

CPR chest compression machines typically hold the patient supine, whichmeans lying on his or her back. Such machines then repeatedly compressand release the chest of the patient. In fact, they can be programmed toautomatically follow the guidelines, by compressing and releasing at therecommended rate or frequency, while reaching a specific depth.

Guidelines by medical experts such as the American Heart Associationprovide parameters for CPR to cause the blood to circulate effectively.The parameters are for aspects such as the frequency of the chestcompressions, the depth that they should reach, and the full releasethat is to follow each of them. If the patient is an adult, the depth issometimes required to reach 5 cm (2 in.). The parameters for CPR mayalso include instructions for the rescue breaths.

International guidelines for performing cardiopulmonary resuscitation(CPR) recommend chest compressions that are consistent and repetitive induty cycle, depth, and rate, among other characteristics. Furthermore,recommendations for hand placement during CPR are not more specific thanpushing in the center of the chest at the sternum. This is, presumably,to press on the heart, or “pump,” that generates blood flow.

The repeated chest compressions of CPR are actually compressionsalternating with releases. The compressions cause the chest to becompressed from its original shape. During the releases the chest isdecompressing, which means that the chest is undergoing the process ofreturning to its original shape. This decompressing does not happenimmediately upon a quick release. In fact, full decompression might notbe attained by the time the next compression is performed. In addition,the chest may start collapsing due to the repeated compressions, whichmeans that it might not fully return to its original height, even if itwere given ample opportunity to do so.

Some CPR chest compression machines compress the chest by a piston. Somemay even have a suction cup at the end of the piston, with which thesemachines lift the chest at least during the releases. This lifting mayactively assist the chest, in decompressing the chest faster than thechest would accomplish by itself. This type of lifting is sometimescalled active decompression.

BRIEF SUMMARY

The present description gives instances of Cardio-PulmonaryResuscitation (CPR), systems, storage media that store programs, andmethods, the use of which may help overcome problems and limitations ofthe prior art.

In certain embodiments, a CPR system includes a retention structure toretain the patient's body, and a compression mechanism to perform CPRcompressions to the patient's chest. The CPR system further includes aprocessor to control the compression mechanism, and thus the performanceof the CPR compressions. The CPR compressions have certain parametersthat describe how the CPR compressions are performed. In certainembodiments, those parameters include, but are not limited to, afrequency at which the compressions occur, a duty cycle of compressionto decompression, a depth of compression, and the like.

In accordance with the disclosure, CPR parameters are dynamicallyadjusted based on physiological signals. In certain implementations, CPRparameters may be dynamically varied based on continuous feedback fromphysiological sensors; or based on sweeps of said parameters acrosstheir domain spaces; or differing CPR protocols based on patient downtime; or the like.

The present description further gives instances of additionalCardio-Pulmonary Resuscitation (CPR), systems, storage media that storeprograms, and methods, the use of which may help overcome problems andlimitations of the prior art.

These and other features and advantages will become more readilyapparent in view of the embodiments described and illustrated in thepresent disclosure taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective diagram of a conventional CPR system.

FIG. 2 shows elements of a diagram in a prior art reference for a CPRsystem.

FIG. 3 shows elements of a diagram in another prior art reference for aCPR system.

FIG. 4 is a diagram showing an aspect of a sample conceptual CPR systemmade according to embodiments, in combination with cooperating aspectsillustrating operations of the CPR system according to embodiments.

FIG. 5 is a time diagram showing a sample time distribution of chestcompressions within a time interval according to an embodiment.

FIG. 6 is a time diagram showing a sample time distribution of chestcompressions within a time interval according to another embodiment.

FIG. 7 is a time diagram showing a sample time distribution of chestcompressions within a time interval according to one more embodiment.

FIG. 8 shows a combination of a time diagram of a sample series ofoutputted consciousness values, along with a time diagram illustratinghow an instantaneous frequency of the performed chest compressions canchange in view of the outputted consciousness values according toembodiments.

FIG. 9 is a diagram of a patient with a sample environmental sensor thatincludes a motion detector according to embodiments.

FIG. 10 is a diagram of a patient with a sample environmental sensorthat includes an electrode according to embodiments.

FIG. 11 is a diagram of a patient with a sample environmental sensorthat includes a close-up camera according to embodiments.

FIG. 12 is a diagram of a CPR system with a sample environmental sensorthat includes a camera according to embodiments.

FIG. 13 shows a combination of a time diagram illustrating how aninstantaneous frequency of chest compressions performed as a test insearch of an optimal frequency can change before the optimal frequencyis determined and adopted, along with a time diagram of a sample seriesof outputted consciousness values that result from the test and informthe determination of the optimal frequency.

FIG. 14 is a view of a sample user interface made according toembodiments.

FIG. 15 is a flowchart for illustrating methods according toembodiments.

FIG. 16 is a flowchart for illustrating methods for finding an optimalfrequency for a dynamic mode according to embodiments.

FIG. 17 is a diagram showing a sample conceptual CPR system madeaccording to embodiments.

FIG. 18 is a perspective diagram of a sample CPR system made accordingto embodiments in which the auxiliary compression mechanism compressesan abdomen of the patient.

FIG. 19 is a perspective diagram of the CPR system of FIG. 18, madeaccording to a sample embodiment where the auxiliary compressionmechanism includes a belt that can be retracted and released by a motor.

FIG. 20 is a perspective diagram of the CPR system of FIG. 18, madeaccording to a sample embodiment where the auxiliary compressionmechanism includes a piston.

FIG. 21 is a perspective diagram of the CPR system of FIG. 18, madeaccording to a sample embodiment where the auxiliary compressionmechanism includes a belt and a piston compressing over the belt.

FIG. 22 shows two time diagrams of sample main compressions andauxiliary compressions that are coordinated according to embodiments.

FIG. 23 shows two time diagrams of sample main compressions andauxiliary compressions that are performed simultaneously according toembodiments.

FIG. 24 is a diagram of a sample sensor being implemented by aventilator according to embodiments.

FIG. 25 is a diagram of a sample sensor being implemented by an NIBPcuff according to embodiments.

FIG. 26 is a flowchart for illustrating methods according toembodiments.

FIG. 27 shows two diagrams comparing a vital statistic being measuredduring CPR to varying CPR compression parameters.

FIG. 28 shows one example of how a score may be used to help improve CPReffectiveness by varying CPR parameters based on physiological feedback.

FIG. 29 is a conceptual illustration of an index plotted against varyingCPR parameters, in accordance with one embodiment.

DETAILED DESCRIPTION

Briefly described, the present disclosure is directed at embodiments ofa mechanical Cardio-Pulmonary Resuscitation (CPR) system that includesmechanisms for dynamically altering CPR compression parameters based onphysiological characteristics of the patient.

The disclosed embodiments pertain to CPR systems that are usable by arescuer to care for a patient. One such system, shown in FIG. 1, isoffered and sold by Physio-Control, Inc. under the trademark Lucas®.

A CPR system 100 includes components that form a retention structure.The components include a central member 141, a first leg 121, a secondleg 122 and a back plate 110. Central member 141 is coupled with firstleg 121 and second leg 122 using joints 181, 182, such that first leg121 and second leg 122 can be partly rotated around joints 181, 182 withrespect to central member 141. This rotation can help minimize theoverall volume of CPR system 100, for easier storage at times when it isnot used. In addition, the far ends of legs 121, 122 can become coupledwith edges 131, 132 of back plate 110.

These couplings form the retention structure that retains the patient.In this particular implementation, central member 141, first leg 121,second leg 122 and back plate 110 form a closed loop, in which thepatient is retained. For storage, back plate 110 can be uncoupled fromlegs 121, 121, which can be further rotated so that their edges arebrought closer to each other.

Central member 141 includes a battery that stores energy, a motor thatreceives the energy from the battery, and a compression mechanism thatcan be driven by the motor. The compression mechanism is driven up anddown by the motor using a rack and pinion gear. The compressionmechanism includes a piston 148 that can compress and release thepatient's chest. In one specific implementation, piston 148 terminatesin a suction cup 199 for active decompression. In this case, certaincomponents—the rack and pinion gear, the battery, and the motor—are notshown because they are completely within a housing of central member141.

Physio-Control's Lucas® system has performed so well in restoring bloodcirculation to the patient that, during the system's operation,sometimes the patient actually wakes up. The reason is that, even thoughthe patient's heart is not beating by itself, the CPR system iseffectively performing the heart's function for the patient and restorestheir circulation. This is a significant milestone in the achievedeffectiveness of CPR systems, and definitely an argument for using CPRmachines over manual CPR. A challenge, however, is that the now-awakepatient experiences the compressions, which tends to be unpleasant orunsettling for a person who is already experiencing a medical emergency.So far, this problem has been addressed by sedating the patient.

FIG. 2 shows elements of a diagram of U.S. Pat. No. 4,326,507. In thepresent document, FIG. 2 shows another CPR system 200 having a platform210, on which the patient (not shown) may be placed on their back. Avertical removable upstanding column or support 221 is attached to theedge of platform 210, thus rising next to the patient. A releasablecollar 243 supports an overhanging beam or arm 241 over platform 210. Aplunger piston 248 emerges from overhanging beam or arm 241, forcompressing downwards the chest of the patient who is supine on platform210.

FIG. 3 shows elements of a diagram of U.S. Pat. No. 6,939,315. In thepresent document, FIG. 3 shows another CPR system 300 having a platform310, on which a patient 382 may be placed supine. A left side 333L of achest compression belt terminates in a left buckle 334L, and a rightside 333R of the chest compression belt terminates in a right buckle334R. The chest compression belt can be buckled by joining left buckle334L together with right buckle 334R. Then a motor (not shown) retractsand releases the buckled belt, so as to constrict and relax the chest ofpatient 382.

Embodiments are now described in more detail.

FIG. 4 is a diagram of an aspect of a conceptual CPR system 400, incombination with cooperating aspects 408, 468 illustrating operationsaccording to embodiments of CPR system 400.

CPR system 400 is usable by a rescuer (not shown) to care for a patient482. As will be appreciated, the rescuer will thus place patient 482 inCPR system 400, and turn on CPR system 400. Afterwards, CPR system 400may operate automatically and largely autonomously, while the rescuer isobserving, making adjustments, possibly sedating the patient if thelatter regains consciousness, performing other tasks, or makinglogistical arrangements for transport and subsequent care of patient482.

CPR system 400 includes a retention structure 440 that is configured toretain a body of patient 482. It will be appreciated that retentionstructure 440 is shown here conceptually, and not implemented by anyparticular configuration, as there can be many ways in which retentionstructure 440 may be implemented. For example, retention structure 440may include a central member, a first leg, a second leg and a backplate. The central member can be configured to become coupled to theback plate via the first leg and the second leg. This could be as shownin FIG. 1, where the back plate can be totally separated from the otherthree components. Or, these components may be capable of being coupledtogether and separable in different combinations, for example usinghinges or not, etc. Or a single leg may be used, for example as shown inFIG. 2 of this document where the patient is retained between platform210 and plunger piston 248. Or a belt may be used to retain the patientfrom the chest onto a back board, back plate or platform, for example asshown in FIG. 3 of this document.

In some embodiments, straps (not shown) may be used to further securethe patient onto a back board, back plate or platform of retentionstructure 440. Such straps may prevent shifting of the patient's bodywith respect to retention structure 440 during the compressions, etc.

CPR system 400 also includes a compression mechanism 448 attached toretention structure 440. Again, it will be appreciated that compressionmechanism 448 is shown conceptually, and not implemented by anyparticular configuration, as there can be many ways in which compressionmechanism 448 may be implemented. Of course, the implementation ofcompression mechanism 448 is preferably done in consideration of theimplementation of retention structure 440.

In some embodiments, compression mechanism 448 is a piston that emergesfrom a housing that is placed against the patient's chest. In suchembodiments, retention structure 440 can include a belt with two endsattached to the housing. In such versions, the belt is wrapped aroundthe back of the patient to encircle the torso.

Compression mechanism 448 can be configured to automatically perform,while the body of patient 482 is thus retained by retention structure440, CPR compressions alternating with releases to a chest of the bodyof patient 482. For example, compression mechanism 448 can be driven bya motor 443.

CPR system 400 may further include a processor (P) 442 coupled toretention structure 440. Of course, processor 442 may be embedded in ahousing of retention structure 440, and so on. Processor 442 may beimplemented by one or more digital logic devices, such asmicroprocessors, digital signal processors, FPGAs, etc. Processor 442may interoperate with an optional memory (M) 441, etc.

As will be described later in more detail, in some versions orembodiments of the invention, processor 442 is capable of operating indifferent modes. In the example of FIG. 4, at least a normal mode 452and a dynamic mode 454 are possible. Dynamic mode 454 is so-named fromthe fact that parameters of CPR compressions delivered in dynamic mode454 may be altered over time based on various circumstances. In oneadvantage, operation in the dynamic mode 454 may provide the opportunityfor preparation and proper sedation of the patient, after which optimalblood flow can be constituted again.

In some versions, processor 442 includes a state machine 450, and isable to choose its mode of operation by a selector 451. In the exampleof FIG. 4, selector 451 has selected normal mode 452.

Processor 442 can be configured to control compression mechanism 448 tooperate in certain ways according to embodiments. Of course, where motor443 is used, processor 442 can be configured to control compressionmechanism 448 by controlling the operation of motor 443.

Controlling compression mechanism 448 according to embodiments is nowdescribed in more detail. First, since the chest compressions areintended for CPR, the controlling can be such that the CPR compressionscause the chest to become compressed by at least 2 cm, at least for anadult. In fact, larger compression depths are advised by the AmericanHeart Association (AHA), such as 5 cm (1″-2″), or even deeper.

Moreover, according to certain embodiments, compression mechanism 448can be further controlled so as to intentionally underperform, at leasttemporarily, from what it could do or at least from what is advised bythe AHA Guidelines. This underperforming can cause the patient to loseconsciousness again by fainting, which can have the advantage that thepatient will become more tranquil and experience less of the unpleasantexperience of the mechanical chest compressions that the CPR systemcontinues to perform on them.

Versions or embodiments can intentionally underperform in this manner ina number of ways. One such way is to reduce the frequency of thecompressions. Another is to reduce the depth of the compressions. Yetanother is to affect the duty ratio of the compressions. One more is acombination of the above. These adjustments can be initiated directly,or after a short pause that will ensure that the patient will again loseconsciousness.

In some embodiments, the frequency of the compressions is reduced. Aconvenient way of measuring the frequency in this art is in the units ofcompressions per minute (cpm). For example, since 15 sec is ¼ of aminute, the average frequency of compressions during a time intervalthat lasts 15 sec can be given by the number of compressions performedduring that interval times 4.

Some particular values for the frequency of chest compressions bycompression mechanism 448 are now described referring to aspect 408,which is a time diagram of compression depths. In aspect 408, time isdepicted in the horizontal axis while depth is depicted in the verticalaxis, increasing in a downward direction. Some sample compressions 425are shown for a first time interval 410, a second time interval 420 thatimmediately follows first time interval 410, and an other time interval430 that is different from both intervals 410, 420.

In some versions, first time interval 410 lasts 15 sec. During firsttime interval 410, the compressions are performed at an averagefrequency between 0.5 cpm and 52 cpm. In fact, instead of 52 cpm, themaximum can be even lower, such as at most 48 cpm, 44 cpm, 40 cpm, oreven lower.

Further, in some versions, second time interval 420 lasts 30 sec orlonger. During second time interval 420, the average frequency isbetween 0.5 cpm and 52 cpm. The maximum could actually be higher, suchas 56 cpm. Or, the maximum can be lower, such as at most 48 cpm, 44 cpm,40 cpm, or even lower.

Moreover, in some versions, other time interval 430 lasts at least 15sec, and often much longer. During other time interval 430, the CPRcompressions can be performed at an average frequency of at least 64cpm.

In FIG. 4, aspect 468 is a time diagram of average frequencies. Inparticular, for each moment on the time axis, an average frequencyaround that moment is computed and plotted for a value on the verticalAVG_F axis.

It will be appreciated how aspect 468 cooperates with aspect 408.Indeed, during the above described first time interval 410, the averagefrequency falls within a lower band TL, which is bounded by frequencyvalues F1, F2. Sample values for F1, F2 were given above. Moreover,during the above described second time interval 420, the averagefrequency falls within the same lower band TL, or a lower band that hasdifferent values, etc. This lower band TL corresponds to CPR system 400underperforming, as was described above. In addition, for times outsidefirst time interval 410 and second time interval 420, the averagefrequency could be at different frequencies, for example at higher bandNL that is bounded by frequency values F3 and F4. This can be true, forexample, for time interval 430. This upper band NL would correspond tonormal operation, F3 could be 60 cpm, and F4 much higher.

It will be further appreciated how aspect 468 also cooperates with statemachine 450 of a yet different aspect in FIG. 1. Indeed, lower band TLcorresponds to one example of dynamic mode 454, while upper band NLcorresponds to normal mode 452.

In aspect 468, suitable frequency values for lower band TL can be foundby performance purposely deficient enough so that the patient does notregain consciousness, but also effective enough so that the patient'sorgans do not sustain damage. The upper frequency values mentioned abovefor F2, if they were those of the heart, are known to not be enough tomaintain consciousness, at least to most people. It should be noted,however, that a person who has fainted is neither dead nor necessarilydying.

In one embodiment, suitable frequency values for upper band NL can befound by performance that aims to improve circulation. For example, AHAGuidelines recommend compressions at 100 cpm.

As all these possible frequency values are taken into effect, it will beunderstood that lower band TL may even overlap upper band NL. In otherwords, F2 could be larger than F3. In the example of FIG. 4, theopposite case is shown only so as to facilitate the initial explanation.CPR system 400, however, can handle bands of different and evenoverlapping values. This way, CPR system 400 is advantageously betterprepared for a range of patients who may have different resting heartrates to begin with, and for whom suitable values for upper band NL andlower band TL may be correspondingly different. In fact, as will be seenlater, in embodiments a CPR system may search to find an optimalparameter for dynamic mode 454 for a specific patient, such as anoptimal frequency.

It should be understood that, in aspect 408, sample compressions 425 areshown generically and not completely, so as to discuss how their totalnumber as related to their average frequency, but not to indicate theiractual distribution over time. More compressions could be included thanwhat is shown, of the same or different depth, duty ratio, etc. Possibletime distributions according to embodiments are now described forcompressions 425, for example within first time interval 410 and secondtime interval 420.

FIG. 5 is a time diagram 501. Diagram 501 shows a sample timedistribution of chest compressions 525 within a time interval 510according to an embodiment. Time interval 510 could be first timeinterval 410, second time interval 420, or both. In diagram 501, allcompressions 525 during time interval 510 are performed at a singlefrequency. The time spacing between any two successive compressions isthe same.

FIG. 6 is a time diagram 601. Diagram 601 shows a sample timedistribution of chest compressions 625 within a time interval 610according to another embodiment. Time interval 610 could be first timeinterval 410, second time interval 420, or both. In diagram 601, duringtime interval 610, compressions 625 are performed in two groups 651, 652at a single frequency, while no compressions are performed during a setpause 656 between two groups 651, 652. Set pause 656 could last at least3 sec, and separate different sets of chest compressions.

FIG. 7 is a time diagram 701. Diagram 701 shows a sample timedistribution of chest compressions 725 within a time interval 710according to another embodiment. Time interval 710 could be first timeinterval 410, second time interval 420, or both. In diagram 701, duringtime interval 710, compressions 725 are performed at seemingly irregulartimes.

In such versions, at least some of compressions 725 are performed at aplurality of instantaneous frequencies. For purposes of this document,an instantaneous frequency INST_F is defined as a time spacing betweentwo successive compressions. It is further preferred that theinstantaneous frequency be defined from similar aspects of suchsuccessive compressions, if available. In the example of FIG. 7, such atime spacing 757 is shown, which is defined from the beginnings of twosuccessive compressions.

In some embodiments, a environmental sensor is provided, and the CPRsystem's performance may change depending on outputs of theenvironmental sensor. In other embodiments, other sensors are provided,and the CPR system's performance may change depending on outputs of theother sensors. Examples are now described.

Returning to FIG. 4, CPR system 400 may further include an environmentalsensor (ES) 446. Environmental sensor 446 is shown conceptually in FIG.4 and, at least from the description that follows, it will be recognizedthat different embodiments of environmental sensor 446 can havecomponents placed at different locations, such as on various positionson the patient, at retention structure 440, etc.

Environmental sensor 446 can be configured to detect a patientparameter, and to output a series of physiological values determinedfrom the detected patient parameter. For example, Environmental sensor446 can be configured to do this after at least 20 of the chestcompressions have been performed.

Environmental sensor 446 can be further configured to be operativelycoupled to processor 442. In such versions, then, processor 442 can beconfigured to receive a series of outputted physiological values. Anexample is now described.

FIG. 8 shows, in combination, a first time diagram 801 and a second timediagram 868, whose horizontal time axes are aligned. The time axis couldstart from the beginning of an event, at which time the patient isdefinitely unconscious, or at a different time.

In diagram 801, a series of physiological values 826 are shown as starsat the times they are generated. These physiological values 826 can havenumerical values in a numerical scale that can initially have highresolution. A possible conversion to a coarser scale, one likely usableby processor 442 or by the attentive rescuer or both, is shown on thevertical axis of diagram 801, in terms of how the likely consciousnessof the patient can be evaluated.

In addition, a threshold value C_THR could be postulated on the verticalaxis, for this and/or other purposes. In this example, C_THR ispostulated at the lower end of the range of values.

In one specific example, physiological values 826 increase progressivelyas CPR compressions are being performed over time, although thisprogress is not necessarily monotonic. The first physiological valuesthat crosses C_THR occurs at time T1. The subsequent one has a valuethat remains above C_THR.

In diagram 868, a time evolution is shown of an instantaneous frequencyINST_F of the performed chest compressions. In this example, theinstantaneous frequency INST_F starts and remains at a fixed value FNuntil time T1. Since the instantaneous frequency has remained constantthen, until time T1, the average frequency has also remained constant atFN. In some versions, this frequency FN could correspond to a frequencywithin upper band NL of aspect 468 in FIG. 4. (In other examples, INST_Fneed not remain constant.)

In some versions, processor 440 can control compression mechanism 448 soas to change a current average frequency of performing the chestcompressions from a first value FN to a second value FT. This can happenif, out of an early and a later physiological value, in some instancesthe later physiological value is different from the early physiologicalvalue. In the example of FIG. 8, the later physiological value occurs attime T1, while the early value can be any value prior to it. At time T1the threshold value C_THR was crossed for the first time.

Referring to diagram 868, in embodiments where physiological signals areused to cause unconsciousness, at time T1, compressions stop entirelyuntil a short time T2 thereafter, to ensure the patient will faintagain. Then, at time T2, compressions resume at a second value FT, whichis less than FN. In other versions, these frequencies FN, FT couldcorrespond to frequencies within upper band NL and lower band TL ofaspect 468 in FIG. 4. This frequency FT can be the current averagefrequency measured over a 15 sec interval.

The time between T1 and T2 is also known as a pause interval. It can be15 sec or shorter. During the pause interval, INST_F=0. Of course,pausing the compressions during the pause interval is optional. Thepause interval occurs after the later physiological value is received atT1, and before T2, which is when the compressions start being performedat a current average frequency having the second value FT.

In the example of FIG. 8, the processor reacted at time T1, which is thefirst time any of the physiological values 826 crossed C_THR. This neednot be the case. In other instances, automatically transitioning to thelower value may have been disabled as a function, as described later inthis document. Moreover, before triggering, it may be desirable to firstaccumulate a number of physiological values in the series and ensureenough of them are above C_THR, for increased reliability.

As seen above, the CPR system's performance may change depending onoutputs of the environmental sensor. In addition, or alternatively, ahuman-perceptible indication may be emitted from a user interface, ifprovided, as described later in this document.

Embodiments are now described for the environmental sensor.

FIG. 9 is a diagram of a patient 982 with a sample environmental sensor946 that includes a motion detector. The motion detector can beconfigured to detect a motion of the patient. The motion can be a signthat the patient is waking up. Placing the motion detector can beperformed with a view to what motions the patient might perform whileawake, and which the patient would not perform while unconscious.Moreover, windows of time can be excluded when the compression mechanismis working, and is thus profoundly shaking the patient's body. Same ifan auxiliary compression mechanism is also used, as described later inthis document.

In other versions, environmental sensor 946 is provided with a clip,adhesive tape, pin, releasable loop of twine or plastic band, or otherattaching means for attaching to patient 982. Attachment could be to thepatient's abdomen, foot, finger, diaphragm, head, etc. In certainimplementations, to assist in a more accurate detection of the patientregaining consciousness, the patient may be instructed by a userinterface to move their foot or fingers (e.g. “MAKE A FIST!”), as willbe described later in this document. The patient would hear such aninstruction only while being conscious, etc.

FIG. 10 is a diagram of a patient 1082 with a sample environmentalsensor 1046 that includes an electrode according to embodiments. Theelectrode can be configured to capture an electrical signal of thepatient, such as an ECG. Certain features of an ECG, such as a QRScomplex can indicate that return of spontaneous circulation (ROSC) hasoccurred, and therefore compressions may be paused completely.

In some versions, the environmental sensor includes a camera that isconfigured to capture an image of the patient. Examples are nowdescribed. In still other examples, environmental sensor includesoptical sensors such as, but not limited to, those used for oximetry(including but not limited to cerebral oximetry) and/or heart ratemonitoring; airway sensors monitoring gas partial pressures (includingend-tidal O2 and CO2, airway pressure, air flow, and/or airwaybiomolecules; ultrasound sensors, images, and/or derived measurements,whether transthoracic, transesophageal, and/or transcutaneous placed inthe thorax, outside the thorax or any other part of a patient's bodyincluding over large blood vessels;_audio recordings of sounds internalto a patient's body; catheter based sensors placed in blood vessels formeasurement of blood flow, blood pressure, blood gas composition, and/ordetection of various biomolecules; and any combination of the abovementioned sensors.

FIG. 11 is a diagram of a patient 1182 with a sample environmentalsensor 1146. Environmental sensor 1146 forms a small housing and has anopening towards the patient's skin. A light inside the housingilluminates the patient's skin. A camera inside the housing, images thepatient's skin from a short distance. The skin color or pallor canindicate circulation, while compressions are taking place and while not.Environmental sensor 1146 can be attached to the patient's skin,avoiding the clothes, for example with a rubber band around anextremity.

FIG. 12 is a diagram of a CPR system 1200 that has a retention structure1240 for a patient 1282. CPR system 1200 has a compression mechanism1248, and a environmental sensor 1246 that includes a camera. The cameracan be implemented as described in copending U.S. patent applicationSer. No. 14/642,027. In such embodiments, then, the camera ofenvironmental sensor 1246 is configured to capture and analyze images ofpatient 1282. These images can be analyzed for evidence of waking up,such as motion of the eyes, change of the patient's place between thecompressions, etc.

In other versions, a environmental sensor may be implemented bymonitoring respiratory parameters, such as airway pressure. An exampleis shown in FIG. 24.

Above, and with reference to FIG. 8, it was described how the processorcan slow down the compressions automatically, so as to increase thepatient's comfort. The reverse can also be true, especially if it isdeemed that the patient's long term well-being cannot afford too muchtime in the slower frequency. An example is now described.

Referring again to FIG. 4, in some versions processor 442 can beconfigured to operate in at least one of a normal mode 452 and a dynamicmode 454. In some versions, while processor 442 operates in normal mode452, it is configured to control compression mechanism 448 to performthe compressions at an average frequency of at least 64 cpm for a timeinterval of at least 15 sec. In some versions, while processor 442operates in dynamic mode 454, it is configured to control compressionmechanism 448 to perform the compressions at an average frequencybetween 0.5 cpm and 64 cpm for a time interval of at least 15 sec. Insuch embodiments, processor 442 can be further configured toautomatically revert to operating in the normal mode, responsive tohaving operated in the dynamic mode for a threshold time duration. Thiscan be useful in the event of a poorly instructed rescuer.

The threshold duration can be, for example 1 minute. In addition, thethreshold duration may be affected by other factors, such as vital signsof the patient, how long the patient was unconscious before CPR system400 was applied to them, and how well optimized were the compressionsduring the dynamic mode—the more optimized, the higher the tolerance fora longer dynamic mode. Accordingly, a score can be kept as to how much,and for how long there was underperformance; when that score reaches athreshold, the CPR system could return to normal mode. In addition,after the patient is sedated, the patient may be able to tolerate longerintervals of normal mode while conscious.

In certain embodiments, CPR system 400 may be configured to find anoptimal frequency for chest compressions in dynamic mode 454. Such anoptimal frequency could, for example, maintain the patient unconscious,while being as high as possible, to maintain as much circulation aspossible. Examples are now described.

FIG. 13 shows a combination of a first time diagram 1368 and a secondtime diagram 1301, whose horizontal time axes are aligned. Thesediagrams of FIG. 13 are similar in nature, but not necessarily similarin purpose, with the diagrams of FIG. 8.

In diagram 1368, a time evolution is shown of an instantaneous frequencyINST_F of the performed chest compressions. These compressions can becharacterized as test compressions. Different instantaneous frequenciescan be tried for the test compressions; in other words, processor 442 isconfigured to control compression mechanism 448 to perform testcompressions such that time spacings between successive ones of the testcompressions have at least two different values.

In the example of diagram 1368, the instantaneous frequency INST_Fstarts at F__TEST_A for some time until time T1, then is reduced toF_TEST_B for some time until time T2, and then reduced further toF_TEST_C for some time until time T3. It will be recognized that, in theexample of FIG. 13 one starts with a conscious patient, and the testcompressions are such that some of the time spacings increase with time.Equivalently, one could start with an unconscious patient, and increasethe test frequencies. In such cases, the test compressions are such thatsome of the time spacings decrease with time.

In diagram 1301, resulting physiological values 1326 are shown. A subsetof physiological values 1326 before time T3 can be characterized as testphysiological values 1327. These are similar in nature to physiologicalvalues 826, but their purpose is testing.

In versions, then, processor 442 can be further configured to determinean optimal frequency F_OPT from at least some of test physiologicalvalues 1327. Indeed, values 1327 inform when various thresholds arecrossed, both with their values and their delay in timing from when theinstantaneous frequency changed. It should be appreciated that theoptimal frequency F_OPT may vary widely between individual patients ofdifferent physical characteristics and physiologies. Moreover, inaddition to the computation of F_OPT, a computation may become availablefor how long F_OPT may be used, before having to revert to the normalmode.

Once optimal frequency F_OPT is determined from test physiologicalvalues 1327 of diagram 1301, its value can be placed on the verticalaxis of diagram 1368, as shown by a bold arrow in FIG. 13. At time T3,then, in diagram 1368, the optimal frequency F_OPT may become adopted asthe instantaneous frequency for some time. In other words, whenoperating in dynamic mode 454, processor 442 can be configured tocontrol compression mechanism 448 to perform the compressions at theoptimal frequency for at least 15 sec, 30 sec, 45 sec or even longer,for first time interval 410 second time interval 420, etc. Plus, duringthat time one may deviate from the optimal frequency, for example byplus or minus a percentage such as 20%.

Those physiological values 1326 that occur beyond time T3 then are,strictly speaking, no longer test values. It would be advisable,however, to monitor them for a long term trend, perhaps adjusting F_OPT,etc.

It will be further recognized that, in some versions, the time from T3and beyond could be time interval 410. In other words, time interval 410need not be the beginning of the event, but instead be a prolonged timewhere compressions are delivered and the patient is tranquil.

Returning to FIG. 4, versions described above are where CPR system 400of FIG. 4 may change its operation autonomously, automatically, even ifthe rescuer does nothing. This may help where a rescuer isinexperienced, and/or where a medical director demands consistenttreatments.

In some versions, CPR system 400 also includes a user interface 404.User interface 404 can be configured to be operatively coupled withprocessor 442, whether by direct wiring or via a communication linkbetween a communication module of CPR system 400 (not shown) and that ofa mobile device, such as a tablet, mobile phone, laptop, etc., whichimplements the user interface.

User interface 404 can be configured to receive one or more controlinputs from a human. It will be appreciated here that the human is therescuer although, in some versions, the human can be the patient who atthe time is receiving chest compressions. In any event, an attentive andexperienced rescuer may exercise as good or even better judgment inmaking decisions that allow the CPR system to execute preprogrammedprotocols.

In such versions, processor 442 can be further configured to change,responsive to the control input received via user interface 404, fromoperating in one of dynamic mode 454 and normal mode 452 to operating inthe other. An example is now described.

FIG. 14 shows a user interface 1404 made according to embodiments.Sections of user interface 1404 may be implemented on a panel located onretention structure 440, on a screen such as a touch screen, and so on.

User interface 1404 has a mode selection section 1414. Section 1414 hasa rotatable selector 1416 that presents the rescuer with an OFF optionfor the system, and an AUTO option. Aspects of the AUTO option weredescribed above, and may permit the CPR system to operate autonomously.In addition, rotatable selector 1416 presents the rescuer with theoption to select a NORMAL mode or a DYNAMIC mode, each of which maydisable the other modes. Selector 1416 may thus provide the controlinput by the user.

In one embodiment, user interface 1404 also has a mode advisory section1424 for the rescuer. Section 1424 has displays for the shown fields ofsuggested mode, consciousness score, and possibly others. In addition,it has alerts for four individual consciousness indicators, namelyMOTION DETECTION, QRS DETECTION, COLOR SKIN DETECTION and EYE MOVEMENTDETECTION. Of these, all are shown as lit, meaning detecting, except theQRS detection.

In section 1424, the computed consciousness score is LIKELY CONSCIOUS,and is an aggregate score. Where, as here, multiple environmentalsensors are available, an aggregate score may be computed from theiroutputs. The individual outputs on user interface 1404 can further helpthe rescuer assess whether a sensor has fallen off, is not working, etc.

In section 1424, the suggested mode is DYNAMIC. Upon seeing this, therescuer may turn selector 1416 to DYNAMIC or AUTO.

In some embodiments, voice commands are also accepted. Examples are nowdescribed.

Referring again to FIG. 4, CPR system 400 may also optionally include avoice recognition module (VR) 405. Voice recognition module 405 may beimplemented in any way known in the art, such as within processor 442,or within UI 404. In the latter case, module 405 may be embedded in atablet, mobile phone, etc. at the time of manufacture.

In such versions, user interface 1424 may include a microphone 1474.Microphone 1474 can be configured to capture a sound as the controlinput of user interface 1424. In such versions, voice recognition module405 can be configured to recognize whether or not the sound captured bymicrophone 1474 resulted from a preset utterance, which could be arecognizable command. If voice recognition module 405 indeed recognizedthe captured sound as having resulted from the preset utterance,processor 442 can be further configured to change from operating in oneof dynamic mode 454 and normal mode 452 to operating in the other.

In some versions, as in the example of FIG. 14, user interface 1404further includes a speaker 1464. Speaker 1464 can be configured to speakan instruction to the patient. The instruction can be to vocalize thepreset utterance, if the patient is unbearably uncomfortable. Forexample, the instruction can be: “IF YOU CAN′T TAKE IT SHOUT: STOP”. Insuch versions, the spoken command “STOP” can be accepted as a validcommand for reverting to the dynamic mode. If the CPR system deems thatthe dynamic mode is not available, the instruction need not be spoken tothe patient, of course.

Returning to FIG. 4, embodiments may also benefit from what is describedlater in this document. For example, embodiments may include auxiliarycompression mechanisms, and so on.

Moreover, methods and algorithms are described below. These methods andalgorithms are not necessarily inherently associated with any particularlogic device or other apparatus. Rather, they are advantageouslyimplemented by programs for use by a computing machine, such as ageneral-purpose computer, a special purpose computer, a microprocessor,etc. These algorithms are not necessarily purely mathematical, and areconfigured to address challenges particular to the problem solved, aswill be apparent to a person skilled in the art. In embodiments, anon-transitory computer-readable storage medium 441, 1741 stores one ormore programs which, when executed by systems or devices according toembodiments, result in operations according to embodiments. Executioncan be by a processor 442, 1742 that reads the storage medium, etc.

This detailed description includes flowcharts, display images,algorithms, and symbolic representations of program operations within atleast one computer readable medium. An economy is achieved in that asingle set of flowcharts is used to describe both programs, and alsomethods. So, while flowcharts describe methods in terms of boxes, theyalso concurrently describe programs.

Methods are now described.

FIG. 15 shows a flowchart 1500 for describing methods according toembodiments. According to an operation 1510, a body of the patient isretained in the retention structure.

According to another operation 1520, there are performed, while the bodyis thus retained, automatically CPR compressions alternating withreleases to a chest of the body, in which during a time interval otherthan the first time interval, the CPR compressions are performed at anaverage frequency of at least 64 cpm. This can also be called operatingin the dynamic mode, and the average frequency can even be 100 cpm.

According to another, optional operation 1530, it is inquired whether toconvert to the dynamic mode. This operation may be implemented in anumber of ways. In some versions, a patient parameter is detected, and aseries of physiological values are output that are determined from thedetected patient parameter. The physiological values may be received,and the answer can be “yes” if one or more of the physiological valuessuggest altering CPR parameters. In versions, that difference may haveto cross a threshold, for example as seen in FIGS. 8 and 13. In someversions the answer is given by a control input that is received from auser interface. If the answer is no, then execution can remain, orrevert again to operation 1520.

If the answer is yes, then according to another, optional operation1540, parameters of the compressions are altered, perhaps temporarily.An example of that was seen in FIG. 8, between times T1 and T2.

Then according to another operation 1550, there may be performedautomatically, while the body is thus retained, CPR compressionsalternating with releases to a chest of the body, in which during afirst time interval, which may last 15 sec, the CPR compressions areperformed at an average frequency between 0.5 compressions per minute(cpm) and 52 cpm. This can also be called operating in anunderperforming mode.

According to another, optional operation 1560, it is inquired whether toconvert to the normal mode. This operation may be implemented in anumber of ways. One such way is with the physiological values, asdescribed for operation 1530. Another such way is to answer yes if athreshold time duration has passed. In some versions the answer is givenby a control input that is received from a user interface. If the answeris no, then execution can remain, or revert again to operation 1550. Ifthe answer is yes, then execution can transfer back to operation 1520,and so on.

FIG. 16 shows a flowchart 1600 for describing methods according toembodiments. The methods of FIG. 16 may be performed in addition tothose of FIG. 15, and especially for establishing an optimal frequency(rate) F_OPT for operation 1550.

According to an operation 1610, test compressions are performed atdifferent frequencies. Such was described with reference to FIG. 13,diagram 1368 above. The frequencies can be ascending, descending, etc.Preferably, frequencies used earlier are also used as test frequencies,by storing their results, etc.

According to another operation 1620, a patient parameter is detected.Patient parameters may be any one or more of various physiologicalcharacteristics of the patient, such as optical sensor based regional orcerebral oximetry (e.g., Sp02, methemoglobin saturation,Carboxyhemoglobin saturation, regional or tissue oxygen saturation);airway monitoring device based end-tidal O2 or CO2, airway pressure,airway flow, airway biomolecules; ultrasound based blood flow or cardiacwall motion measurements; ECG or defibrillation lead based transthoracicimpedance measurements; catheter based measurements of blood flow, bloodpressure (both non-invasive blood pressure and invasive blood pressuremeasurements), blood gas composition, blood ion composition, and/orblood biomolecule composition; audio signal based blood flow,ventilation, and cardiac motion measurements; pulse or heart rate,respiration rate, body temperature, and any combination of the above.

According to another, optional operation 1630, test physiological valuesare output, which are determined from the detected patient parameter andare associated with the performed test compressions. Such were seen asvalues 1327 above.

According to another operation 1640 an optimal frequency may bedetermined from at least some of the test physiological values. Such adetermination can be elaborate, or simply be the first value thatyielded a satisfactory result. Optionally, this value can be usedafterwards, for example for the dynamic mode during the first interval.

In other embodiments, the chest compressions could be varied during theprocess of CPR. in one example, they could be varied continuously. Somepreviously suggested variations describe two or three different distincttypes of chest compression patterns that comprise a “cycle” of someduration. The different cycles are repeated in some sequence to deliverchest compressions which vary over time but have some repetitivepattern. In another embodiment, n (where n=1:∞) distinct types of chestcompression patterns can exist, which can be repeated or not repeated inany permutation. In another embodiment the chest compression parametersthat are varied (i.e., rate, depth, pauses, release velocity,compression velocity) would be varied continuously in some way. In oneembodiment the parameter(s) could be varied continuously in monotonicincreasing or decreasing patterns over time. For example, the rate wouldcontinuously increase or decrease. In another embodiment the chestcompression parameters would be generated randomly within predefinedlimits (FIG. 2c ). In still another embodiment the chest compressionparameters may change in a non-monotonic fashion during the time courseof CPR.

In additional versions of the invention, the compression velocity andthe release velocity could be varied. One embodiment is a mechanism andmethod to control a mechanical CPR device to provide chest compressionsin which the rate a chest compression is performed and the rate at whichthe compressed chest is decompressed can be adjusted over time tooptimize hemodynamics for different parts of the body or for improvedhemodynamics overall. In on embodiment the chest decompression ispassive, in another the decompression is active (i.e., facilitated by amechanism such as a suction cup or adhesive pad). In another, the chestcompression release velocity is adjustable with an adjustable finalposition above the normal chest height following recoil from theprevious compression.

In additional versions of the invention, a chest compression pattern mayfacilitate diagnosis. Time-varying chest compressions can be adjusted tofacilitate use of technologies to visualize and interpret the underlyingECG waveform in the presence of chest compression artifact. At certaintimes, the compression parameters may remain constant for a set periodof time so as to allow a filtering technology to be used on a monitoringdevice (such as a LIFEPAK15®, etc.) to display ECG without chestcompression artifact and either allow the monitor device or the careprovider to make an assessment as to the shockability of the underlyingrhythm. In another embodiment, the chest compression device could send asignal to the monitoring device indicating the compression parameterswhere the monitoring device could use that information to adjustfiltering parameters to exclude chest compression artifact under varyingcompression parameters.

In another embodiment the chest compression pattern would include abrief pause and during which time patient monitoring devices would makemeasurements, report values, and/or make a treatment decision based onthe presence of return of spontaneous circulation (ROSC). Monitoringtechniques would be combined with the interpretation of the ECG signaland include: ultrasound imaging for detection of cardiac wall motion,heart valve motion or brain markers (EEG, oximetry and more), blood flowin other parts of the body; video or photograph based assessment of skinpallor; and auscultative techniques for detecting blood flow or heartsounds. If ROSC is detected chest compressions are stopped, if ROSC isnot detected chest compressions resume.

In additional versions of the invention, chest compressions could bevaried during the process of CPR for other reasons. For example, heartfilling and emptying can be optimized cyclically and not just tooptimize blood flow to specific organs like heart, lung, or brain. Inversions, long (60, 70, 80% compressions duty cycle with or without rateadjustment) compressions may facilitate a longer period for bloodejection, while long (60, 70, 80% decompressions duty cycle with orwithout rate adjustment) decompressions may facilitate a longer periodfor heart filling.

In additional versions of the invention, chest compressions may beperiodically slowed to facilitate better ventilation. A synchronizationsignal may be sent to a ventilator device or feedback device (forventilation prompts during bag mask ventilation) to improve timing andprovide better ventilation (with lower airway pressures, higher TDvolume) during the prolonged decompression phases of chest compressions.

In additional versions of the invention, as chest compressions becometime varied, temporary changes in compression parameters peri-shock canbe used to avoid difficulties with coordinating with shocking, and thusfacilitate defibrillation. There is currently a scientific debateconcerning continuous chest compressions during defibrillation. It hasbeen suggest that providing chest compressions during defibrillationdecreases shock success, still others suggest that chest compressionsshortly after defibrillation may reinitiate fibrillation. On the otherhand, stopping chest compressions peri-shock has been shown to bedetrimental for patient survival (although this is likely true for chestcompression pauses other than peri-shock pauses). The risk can bereduced, however, by synchronizing a chest compression device with adefibrillator as follows: the chest compression pattern could be alteredto not-compress the chest during the vulnerable time periods whileminimizing or eliminating pauses by utilizing a waveform optimized for aspecific purpose (such as optimal heart filling) peri-shock.

In additional versions of the invention, chest compressions could bevaried during the process of CPR to minimize injury while maintainingacceptable blood flow. Or, if optimal hemodynamics can be achieved at awide range of chest compression parameters the parameters would then benarrowed further with the goal of simultaneously maximizing blood flowand minimizing such injury. This embodiment should be combined with thepossibility of targeted maximization of blood flow to specific organs aswell as overall cardiac output.

Dynamically Altering CPR Compression Parameters Based on PysiologicalSignals

In certain embodiments, chest compressions could be varied during theprocess of CPR based on physiological signals that describe variouscharacteristics of the patient. Varying chest compression parameters mayresult in different blood flow parameters for different chestcompression parameters. Measuring the physiological state of the patientwhile performing CPR may enhance the effectiveness of the CPR, which canpotentially diminish permanent organ damage. Cardiovascular systems ofdifferent individuals will vary based on a whole array of conditions,such as down-time, inherent anatomical differences, various states ofbeing (e.g. filled vs. empty lungs, elasticity of blood vessels, reasonfor cardiac arrest, etc). Therefore, it may benefit a cardiac arrestpatient to receive CPR that varies as described above, but also based ontheir physiologic response to the CPR.

Embodiments implement physiological signal feedback in various ways,such as, for example, providing continuous feedback of the patient'sphysiological characteristics (e.g., cerebral oximetry, EtCO2, or thelike) which are used to vary CPR compression parameters in real time. Inanother alternative, CPR compression parameters may be varied throughsweeps of said parameters across their domain spaces. In yet anotheralternative, different CPR protocols may be used based on patient downtime. Each of these alternatives will now be described in greater detailhere, with still other alternatives being made apparent from theseteachings.

For the purpose of this document, “optimization” may have differentmeanings throughout the resuscitation, since different markers ofphysiologic feedback can provide different insights into patient status.Accordingly, “optimization” of CPR parameters does not necessarily meanthat the CPR parameters achieved are necessarily the absolute optimumfor either a particular patient or even a particular circumstance.Rather, “optimization” in this context means seeking to improve one ormore characteristics of the quality of the CPR being delivered to apatient.

Compression Optimization through Continuous Feedback (i.e., CerebralOximetry, EtCO₂, etc.)

As noted above, one or more physiological sensors may be attached to thepatient to measure, either continuously or intermittently, vital signs(e.g., physiological characteristics) of the patient. Signals from thesephysiological sensors can include, but are not limited to, ECG,transthoracic impedance, capnography, pulse oximetry, cerebral oximetry,blood pressure, and heart or pulse rate. These signals are used tocharacterize patient status, such as shockable versus nonshockablerhythms, coarseness of ventricular fibrillation, estimates of relativemovement of blood, etc. In addition, they are used to identify whether agiven treatment is working or has worked; for example, conversion ofheart rhythm, return of spontaneous circulation (ROSC), generation ofblood flow, etc.

The present embodiment incorporates one or more of these signals asfeedback to the processor 442 to continuously optimize/de-optimizetreatment. In general, the pattern is such: after some time of treatment(w), if a physiologic signal of interest (x) is not above a threshold(y), a certain CPR parameter (z) is varied (either through optimizedsweeps (as discussed below), or through predetermined correlations thatare known to exist between x and z), to see if y can be reached. If y isnot reached, then a different CPR parameter is varied with x. If y isreached, a new x and corresponding z pair are analyzed in a similar way,until preferable as many parameters have been optimized as is practical.

In one enhancement, if optimizing an {x(m), z(m)} pairing results in asuboptimal {x(n), z(n)} pairing, then parameters can be varied with timeto oscillate between optimization/de-optimization of differing pairings.For example, if one type of compression parameter (e.g. quickcompressions) is determined to optimize/de-optimize the perfusion of thebrain, and cerebral oximetry values are low (e.g. <25%), the CPRprotocol can be updated to deliver faster compressions for a largerproportion of CPR time.

Referring now to FIG. 27, a given vital sign (cerebral oximetry in thisexample) is shown 2701. As CPR compressions are being delivered at afirst frequency 2711, the vital sign (2702) is below a certain threshold(2704). At a different point in time, CPR compressions are delivered ata second frequency 2712, and the resulting cerebral oximetry valuesincrease 2706.

In another enhancement, embodiments attempt to optimize CPR compressionsbased on a combination of vital signs, rather than by attempting toindividually optimize each vital sign. For example, a multi-dimensionalscore could be generated based on a plurality of measured vital signs,which will consequently put a patient in a quadrant. Based on thequadrant the patient is in (e.g. high EtCO2, low svO2, VF, etc.), aspecific type of compression may be advantageous (e.g. shallow, quickcompressions, with a long piston-down time).

Compression Optimization through Scans/Sweeps of Compression Parameters

In another embodiment, rather than optimizing each aspect of CPR basedon physiologic signals, CPR parameters are varied in an organizedfashion (e.g. a sweep of compression frequencies across a wide range),to try and determine which combinations result in a good response fromthe vital signs. Referring now to FIG. 28, one example of this is tobegin compressions with a given set of parameters (e.g., at a set rate,depth, and duty cycle). Then vary one of these parameters (e.g. rate2805) in predetermined increments (e.g, by 10), staying within a rangedeemed to be safe, while keeping the other parameters constant.

The CPR compressions may be delivered at each rate for a period of timesufficient in length for the vital sign(s) of interest to respond to thechange and stabilize at a new level. By way of example, this could be atime between 10 seconds and 2 minutes, approximately. A score (e.g.score 2811) can be assigned to each parameter at the particular deliveryvalue based on the corresponding vital signs. In one embodiment, thecompression configuration that achieves the highest score is chosen foruse during treatment.

As shown in FIG. 28, a first compression rate results in a score of4/10, a second compression rate results in a score of 3/10, and a thirdcompression rate results in a score of 6/10. Accordingly, the thirdcompression rate (which has the most favorable score) is chosen for useduring treatment.

This process can be repeated for each of the parameters in the set ofvariable parameters. In such a way, the entire set of parameters may beoptimized/de-optimized individually. In another implementation, ifoptimize/de-optimize one parameter results in a suboptimal use of adifferent parameter, these parameters can be oscillated back and forthin time, to capitalize on both configurations.

To visualize this process, one embodiment optimizes a vital sign (orindex combining multiple vital signs) over a space of two compressionparameters, as illustrated in FIG. 29. The 3D plot shown in FIG. 29would have two compression parameters (for example rate and depth) asthe two axes of the horizontal plane, and the vital sign or index isplotted as height above that plane. If the optimum combination for avital sign related to the brain, for example, differs from the optimumfor a vital sign related to the heart, it may be beneficial to alternatebetween those 2 types of compressions.

In one embodiment, the index is a function of the multiple patientphysiological signals sensed by multiple sensors. For example, the indexmay be a function that combines various values of measured physiologicalsignals, with different weights given to each of the patientphysiological parameters. In another embodiment, these weights may varydepending on the selected optimization (e.g., a heart optimum versus abrain optimum).

In another embodiment, the index may be derived based on a perceivedorder of importance of each physiological parameter; in other words apriority index. For example, if perfusing the brain is a first priorityand pulmonary perfusion is a second priority, an acceptable thresholdcan then be set for the cerebral oximeter value (rSO2). The process maybegin with guidelines-based CPR and mix in perhaps a 3 to 15 secondsegment of CPR “optimized” for brain perfusion (brain CPR). Theresulting rSO2 can be observed and if it's above threshold, brain CPRcan be mixed in every 30 sec to 1 min. If it's below threshold, theduration of brain CPR can be increased, to say 6 to 20 sec, or repeatmore frequently, say every 15 to 30 sec, until the threshold is reachedor a maximum value is reached. The process can then repeat using EtCO2to optimize pulmonary perfusion.

The perfusion priority of each organ system in the above approach todetermining a priority index could also be modifiable by the monitoredphysiological parameters. For example, if it's observed that sO2 is low,and/or EtO2 is very low it could be determined that more oxygen needs toreach the blood so CPR that enhances blood flow to the lungs could beprioritized above other organs until one of these values rises abovethreshold after which pulmonary perfusion is no longer first priorityand another parameter becomes prioritized.

The priority index could also be used to determine the relative durationor percent mixture of each type of chest compression in the overall CPRprotocol. For example, if the priority index prioritized the brain, thenthe heart, then the lungs, 45% of the time could be spent doing CPRoptimal for the brain, 30% CPR optimal for the heart, and 25% CPRoptimal for the lungs, in just one of many examples.

Another alternative approach—if, for example, it was unknown how to dooptimal CPR—is to monitor the percent change in each physiologicalparameter based on various modifications to chest compression parametersand weight them accordingly. In other words, a combined index can bederived by weighting each physiological parameter according to howsensitive it appears to be to modifications in chest compressioncharacteristics. In this case the index might just be a weighted averageof the percent change from baseline form all of the monitoredphysiological parameters. Many additional alternatives will becomeapparent to those skilled in the art from the foregoing examples andillustrations.

Considering the teachings of the present disclosure, one of skill in theart can visualize various strategies for covering the parameter space,recognizing that approaches that most efficiently find the optimalcombination would be strongly desirable. This becomes even more relevanta consideration as the parameter space increases from the two parametersshown. Additional parameters may also be included, such as duty cycle ofthe compressions, amount of lifting above neutral chest height, locationof application of force on the thorax, etc.

Incorporation of Various CPR Protocols Based On Patient Down Time

Time spent without perfusion can have a quick and drastic impact on thebody. After prolonged downtime, the metabolic phase of cardiac arrest isreached, and different CPR treatments may be beneficial to a patient.For example, after a long down-time, followed by reintroduction ofoxygen through blood flow, reperfusion injury is a danger to thepatient. Experiments have indicated that controlled-pause CPR (such asintroducing 20 second pauses during the first 3 minutes of CPR) canimprove survival with good neurological outcome in swine. Although theactual cause is unknown, it is theorized that this treatment evokes an“ischemic conditioning response” that reduces the amount of injurycaused by reperfusing the ischemic tissue.

To that end, certain embodiments may be implemented with different CPRprotocols built in based on down-time. These protocols can be initiatedmanually, based on, for instance, dispatch to arrival time, orautomatically, based on, for instance, the coarseness of VF. These modeswill allow for the CPR to be optimized to patients who may needdifferent treatments.

In one implementation, protocols are used that are designed to evokeischemic conditioning in cases where the patient down time is long, butmore conventional protocols are used when patient down time is short.For example, controlled pauses mentioned above could be automaticallyadded to the protocol if down time is longer than some threshold, suchas 10 minutes or the like.

Another approach is to automatically deliver compressions that provideonly a little flow for the first few minutes of a case with long patientdown time. Examples of this are compressions at a rate and/or depthsubstantially less than the accepted rate and depth described in theguidelines for emergency cardiac care; for instance use a compressionrate of 60 instead of 100, and a depth of 1.25 instead of 2 inches.

Still another implementation is to alternate between periods of“guidelines compressions” (100/minute and 2 inches deep) and periods of“low flow” compressions, such as 60/minute and 1.25 inches. These andother examples will become apparent from the teachings of thisdisclosure.

Combining Embodiments with Other Technologies

In additional embodiments, time varying chest compressions can becombined with additional technologies and therapies designed to improveCPR, for example: Intermittent Positive End-Expiratory PressureVentilation.

The disclosed solution is to perform intermittent positiveend-expiratory pressure ventilation (PEEP). As the chest compressionsare varied over time, alveolar recruitment maneuvers may automatically(or manually) become synchronized with chest compressions. For example,if the chest compression pattern includes slow compression rates,intermittent PEEP could be performed between compressions.Alternatively, the chest compression pattern may include pauses orprolonged decompression during which time PEEP could be delivered. Theidea is to synchronize the PEEP delivery through feedback from the chestcompression device and automatically perform the ventilations at theright time to optimize re-recruitment of alveolar tissue. Alternativelythe feedback from a chest compression device could be used to control anindicator that would convey timing information to a human care providerdoing ventilation manually by bag mask ventilation or a manual drivenventilator.

As background for PEEP, during CPR, CO₂ ventilation and O₂ delivery areimportant aspects of achieving positive outcomes for the patient. Whileachieving optimal blood flow is critical for this process, the lungsplay a key role by providing the mechanism of gas exchange between theventilated air and the blood. During CPR, chest compressions causesignificant formation of atelectasis in the lung alveoli. This means thealveoli, the small sacks of lung tissue in which gas exchange occurs,are collapsed and can no longer exchange gases. A treatment to minimizeand re-recruit alveolar tissue into this process can be positiveend-expiratory pressure ventilation (PEEP). Unfortunately during chestcompressions, PEEP can be detrimental as chest compressions increaseintrathoracic pressure and reduce venous return to the heart. Theembodiments described above, however with intermittent PEEP can overcomethis.

In additional versions of the invention, time varying chest compressionscan be combined with additional technologies and therapies designed toimprove CPR, namely for timing mechanisms for pharmacologicaltreatments. Embodiments include a mechanism and method for controllingthe timing of pharmacological agent administration which can beperformed either automatically or manually. As such, the timingmechanism should include a control mechanism and automatic deliverymechanism or indicator mechanism to communicate timing to a user. Thetiming of pharmacological agent administration would be dependent on theadministered agent and its intended purpose and its relationship to thetime varying chest compressions. For example, if the chest compressionparameters are cycling between values optimized for systemic flow andvalues optimized for cerebral flow and epinephrine is going to be thedelivered compound, the delivery timing could be controlled such thatdelivery occurs during compressions optimizing systemic flow. Thepurpose may be to preferentially deliver epinephrine to the systemicblood vessels to induce vasoconstriction while reducing vasoconstrictionin the brain, with the end result being enhanced blood flow to thebrain. As background of the above, an important consideration during CPRis the delivery of pharmacological agents to the patient to promotebetter outcomes. Commonly used agents include vasoactive andanti-arrhythmic drugs and sometimes sedatives.

In additional versions of the invention, time varying chest compressionscan be combined with additional technologies and therapies designed toimprove CPR, namely an impedance threshold device (ITD). Intrathoracicpressure is an important determinant of venous blood return during CPR.The impedance threshold device (ITD) is designed to decreaseintrathoracic pressure during the decompression phase of CPR chestcompressions. The ITD works by means of a pressure release valvepreventing, until a certain pressure threshold is reached, air flow backinto the lungs during the decompression. The decreased intrathoracicpressure creates a suction mechanism drawing blood back towards theheart through the venous system. The ITD could be combined with timevarying chest compressions to enhance the desired effects of timevarying compressions by being switched on or off. In the on mode, inwardairflow would be limited based on pressure threshold and in the offmode, airflow would be allowed to freely pass through the device. Forexample, if the goal of the time varying compressions was to alternatebetween optimal cerebral blood flow and optimal pulmonary blood flow,the ITD could be turned on to increase pulmonary flow, and off toincrease cerebral blood flow. This might work by increasing venousreturn and RV ejection volume consequently leading to greater pulmonaryflow when the ITD is turned on and chest compression optimized for RVfilling are performed. On the other hand, when the ITD is turned off,cerebral blood flow would be enhanced by performing brain flow optimizedchest compression and reducing RV filling leading to lower centralvenous presser and hence increasing the cerebral perfusion pressure.

In additional versions of the invention, time varying chest compressionscan be combined with additional technologies and therapies designed toimprove CPR, namely horizontal acceleration CPR. In embodiments, thepatient would be subjected to oscillating horizontal accelerations inthe supine position as an alternative to chest compression based CPR.This type of CPR is referred to as pGz CPR. While the mechanism by whichpGz CPR is not well understood, there is evidence that it stimulatesendothelial cells which release factors that cause vasodilation. Thehorizontal accelerations could be varied in intensity, duration,direction, etc. in coordination with the varying chest compressions. Forexample, if optimal cerebral blood flow is desired, horizontalacceleration in the caudal direction could be synchronized in time withchest compressions could be performed to direct more blood to the brain.Depending on the speed necessary, this can be performed by devicesrevealed in copending Ser. No. 14/273,593 (and in particular FIGS. 8A &8B).

In additional versions of the invention, time varying chest compressionscan be combined with additional technologies and therapies designed toimprove CPR, in particular: Enhanced External Counter-Pulsation (EECP).The idea behind EECP is to apply compressions or constrictions atvarious parts of the body to enhance the effectiveness of CPR.Constrictions are typically applied using inflatable cuffs or garmentsand are timed aligned in some fashion to chest compressions or intrinsicheart rhythm depending on the patient condition. In embodiments, timevarying EECP can be synchronized with time-varying chest compressions.In versions, if the chest compression pattern is alternating betweenheart filling and heart emptying, EECP could be performed to enhancethis effect by having a duty cycle with >50% constriction during heartemptying compressions and >50% during heart filling compressions. Inanother version, if the time varying compressions are alternatingbetween lung perfusion and brain perfusion, EECP could implemented tostay constricted to direct flow to the brain or pulse at 90 degree phaseshift to enhance blood flow to the lungs. In embodiments, the EECP isvaried over time in a way to enhance the intended effects of timevarying chest compressions.

In additional versions of the invention, the embodiments presented abovecould be combined in any permutation, or all be combined together withor without time varying chest compressions. For instance, pGzCPR+ITD+EECP could be synchronized with time varying chest compressionto maximize blood flow. This could be achieved by performing cerebralperfusion optimized time varying compressions, constricting the cuffs inEECP, caudal acceleration in pGz, and having the ITD in the off mode. Inembodiments, combinations of such interventions can be varied to controlthe movement of blood within a patient, thereby optimizing blood flowfor desired purposes. In one version, blood may be directed from thelungs, to the heart, and to the brain in a cyclical fashion, so as tooptimize blood gas exchange, improve the condition of the heart inpreparation for successful defibrillation, and keep the brain alive soas to optimize the chance for neurologically intact survival.

FIG. 17 is a diagram of an aspect of another conceptual CPR system 1700according to embodiments. CPR system 1700 is usable by a rescuer (notshown) to care for a patient 1782, similarly for how it was written forCPR system 400.

CPR system 1700 includes a retention structure 1740 that is configuredto retain a body of patient 1782. Retention structure 1740 is shown hereconceptually, similarly to what was described for retention structure440.

CPR system 1700 also includes a main compression mechanism 1748 that isattached to retention structure 1740. Again, main compression mechanism1748 is shown here conceptually, similarly to how compression mechanism448 was shown. Main compression mechanism 1748 may be implementedsimilarly to what was described for compression mechanism 448.

Main compression mechanism 1748 can be configured to perform, while thebody of patient 1782 is thus retained by retention structure 1740,automatically main compressions alternating with releases to a chest ofthe body of patient 1782. For example, main compression mechanism 1748can be driven by a main motor 1743.

These main compressions that are performed by main compression mechanism1748 are CPR compressions, of the type described for the CPRcompressions performed by compression mechanism 448. For example, thesemain compressions can cause the chest to become compressed by at least 2cm and possibly deeper, as described for the CPR compressions performedby compression mechanism 448.

CPR system 1700 additionally includes an auxiliary compression mechanism1747. Auxiliary compression mechanism 1747 is distinct, different frommain compression mechanism 1748. Auxiliary compression mechanism 1747can be coupled to retention structure 1740.

Auxiliary compression mechanism 1747 is configured to perform, while thebody of patient 1782 is retained by retention structure 1740,automatically auxiliary compressions alternating with releases to thebody. In other words, the body could be receiving main compressions frommain compression mechanism 1748, auxiliary compressions from auxiliarycompression mechanism 1747, or both. As will be seen later in thisdocument, in some versions, the main compressions can be performed incoordination with the auxiliary compressions for a combined medicaleffect. This effect can be further propelling the blood, orstrategically constricting certain pathways.

In some versions, CPR system 1700 further includes a power supply 1778.Power supply 1778 can be configured to deliver power to both maincompression mechanism 1748 and auxiliary compression mechanism 1747.

In some versions, while main motor 1743 is configured to drive maincompression mechanism 1748, CPR system 1700 also includes an auxiliarymotor 1749 configured to drive auxiliary compression mechanism 1747. Insuch versions, power supply 1778 can be configured to deliver power toboth main motor 1743 and auxiliary motor 1749. In other versions, mainmotor 1743 is configured to drive both main compression mechanism 1748and auxiliary compression mechanism 1747.

In some versions, CPR system 1700 further includes a user interface1704. User interface 1704 can be configured to receive a user input fromthe rescuer. In such versions, an operation of one of main compressionmechanism 1748 and auxiliary compression mechanism 1747 is changedresponsive to the user input differently than the other. In other words,the user input can affect the differently, for example only one or theother.

In some versions, auxiliary compression mechanism 1747 is implemented inways similar to what has been described as possible for main compressionmechanism 1748. For example, auxiliary compression mechanism 1747 caninclude a piston, a belt, and so on. In other words, it is possible thatauxiliary compression mechanism 1747 is implemented similarly to, ordifferently from how main compression mechanism 1748 is implemented.

In other versions, auxiliary compression mechanism 1747 is implementedin other ways, according to what is needed and what can cooperate withmain compression mechanism 1748. For example, auxiliary compressionmechanism 1747 may include a load-distributing band. Or it may includean inflatable bag, and the auxiliary compressions can be performed byinflating the bag in such a way that, upon being inflated, the bagcompresses the patient's body in some way, by constricting blood flow,or against retention structure 1740, etc.

In general, the main compressions could be performed at a first location1788 of the chest of the patient's body, while the auxiliarycompressions could be performed at a second location 1787 of the body.Second location 1787 depends on the application.

In some versions, auxiliary compression mechanism 1747 is intended forCPR, in other words the auxiliary compressions are also CPRcompressions, in coordination with the main compressions. In suchversions, main compression mechanism 1748 could include a first piston,while auxiliary compression mechanism 1747 could include a secondpiston. The first and the second pistons could be supported by a portionof retention structure 1740, which could be made as central member 141or overhanging beam 241.

In addition to pistons, or in lieu of the pistons, load-distributingbands can be used. One or more of these pistons can be combined with aload distributing band, to which the piston can be attached or detached,overlapped or alternated in space, to capitalize on blood flow generatedby cardiac compression, and by intrathoracic pressure. Load-distributingbands have the advantage that they emulate better changes inintrathoracic pressure, at least when compared to pistons that emulatecardiac compression better, given that both mechanisms could be at playin generating blood flow.

In such cases, the auxiliary compressions can also be performed to thechest of the body. In such cases, main compression mechanism 1748 andauxiliary compression mechanism 1747 can compress independently of eachother, or based on feedback from one another. Accordingly, multiplecompression mechanisms may optimize CPR for the multiple system of theheart.

In such cases, first location 1788 could even overlap in part withsecond location 1787, as both compression mechanisms try to reach theheart, for example the left side and the right side of the heart. Ifcenter points could be defined for first location 1788 and secondlocation 1787, then a distance between the center points could bemeasured along a surface of the patient's body, and such a distancewould be of the order of a few centimeters. Both pistons could bevertical, to facilitate filling and emptying of the chambers, orsomewhat angled with respect to each other so that they both reach thesame area.

An advantage of multiple, i.e. two or more, compression mechanisms isthat they may be able to work together with synergies. Because the rightand left sides of the heart feed separate circuits, but are ultimatelyattached, controlling the output of one may dictate characteristics ofthe output of the second. The output of the right side of the heart(which is determined by its input) may add a variable to the input andsubsequent output of the left side of the heart, and vice versa.Therefore, two separate devices may allow for modulation of the inputsand outputs of these systems that one alternating piston cannot offer.

For example, one key question about CPR is whether retrograde flowoccurs during the release phase of the compression (or perhaps at adifferent time, or from different types of compressions). It may also betrue that backflow will or will not occur based on the pressure appliedto one side of the heart. For example, if the right side of the heart issqueezed and held at the appropriate time, while the left side iscontinuously pumped with a separate device, it may be feasible todeliver a strong flow in one direction.

Another benefit of having two separate systems can best be illustratedby addressing the left and the right sides of the hearts separately. Thechambers on either side have different characteristics, includingthicknesses, elasticities, and volumes. The circuits that they feed(pulmonic vs. systemic) have entirely different vascular structures andsizes and consequently resistances, and capacitances. Accordingly, eachside could have its own optimal input and resulting output. Therefore,the two sides of the heart may be pumped, even continuously, but withdifferent combinations of patterns as described in previous and currentapplications.

In addition, the filling of the chambers (atria and ventricle), the rateof the filling, the emptying, and the rate of the emptying, all haveimplication on blood flow. In a different configuration, where thecompression mechanisms are oriented horizontally, they could be used intandem, similarly as to the description above, in order to facilitatefilling and emptying of these chambers.

In some versions, retention structure 1740 includes a back plate that isconfigured to receive the patient supine. In such versions, auxiliarycompression mechanism 1747 is coupled to the back plate, and locatedsuch that the auxiliary compressions are performed to an abdomen ofpatient 1782. In other words, in such versions, second location 1787 isat the abdomen. An example is now described.

FIG. 18 is a perspective diagram of a CPR system 1800. CPR system 1800includes a back plate or platform 1810 that is configured to receive apatient 1882 supine. A main compression mechanism 1848 is configured toperform main chest compressions at a first location 1888 on a chest ofpatient 1882. An auxiliary compression mechanism 1847 is configured toperform auxiliary chest compressions at a second location 1887 on anabdomen of patient 1882. In this case, the first location 1888 andsecond location 1887 do not overlap, and are more than a few cm awayfrom each other.

An advantage of multiple compression mechanisms is thus that the abdomencan also be pumped. This is because, although the heart represents thenatural pump that supplies blood to the body, during cardiac arrest theheart is no longer an effective pump. Compressions provide an artificialpumping mechanism, but they do not inherently preclude other organs frombecoming effective synthetic pumps when compressed.

In CPR system 1800, auxiliary compression mechanism 1847 may beimplemented as described above. Two examples are now described in moredetail.

FIG. 19 is a perspective diagram of a CPR system 1900. CPR system 1900includes a back plate or platform 1910 that is configured to receive apatient 1982 supine. A main compression mechanism 1948 is configured toperform main chest compressions at a first location 1988, similarly withFIG. 18.

An auxiliary compression mechanism is also provided, which is configuredto perform auxiliary chest compressions at a second location 1987 on anabdomen of patient 1982. In FIG. 19, the auxiliary compression mechanismincludes a motor 1993, and a belt that serves as a load-distributingband. In particular, a left side 1947L of the belt has been buckledtogether with a right side 1947R of the belt by a buckle 1934. Thenmotor 1993 retracts and releases the buckled belt, so as to constrictand relax the abdomen of patient 1982.

FIG. 20 is a perspective diagram of a CPR system 2000. CPR system 2000includes a back plate or platform 2010 that is configured to receive apatient 2082 supine. A main compression mechanism 2048 is configured toperform main chest compressions at a first location 2088, similarly withFIG. 18.

An auxiliary compression mechanism 2047 is configured to performauxiliary chest compressions at a second location 2087 on an abdomen ofpatient 2082. In FIG. 20, the retention structure further includes anarm 2021 configured to become coupled to back plate 2010. Auxiliarycompression mechanism 2047 includes a piston that is coupled to arm2021.

In some of these versions, auxiliary compression mechanism 2047 furtherincludes a suction cup 2098 that is coupled to the piston. Suction cup2098 can be configured to lift the patient's abdomen during the releasesthat alternate with the auxiliary compressions. Note that suction cup2098 is not necessarily similar to suction cup 199 of FIG. 1. Indeed,suction cup 2098 is shaped differently so as to grab and lift thestomach of the patient. This lifting can help also with rescue breaths,as a ventilator may become less necessary.

FIG. 21 is a perspective diagram of a CPR system 2100. CPR system 2100includes a back plate or platform 2110 that is configured to receive apatient 2182 supine. A main compression mechanism 2148 is configured toperform main chest compressions, similarly with FIG. 18.

An auxiliary compression mechanism 2150 is configured to performauxiliary chest compressions at a second location 2187 on an abdomen ofpatient 2182. In FIG. 21, a belt made from a right belt 2147R and a leftbelt 2147L is buckled by a buckle 2134, and operates as aload-distributing band. A motor 2193 may retract and release the belt.In addition, the retention structure further includes an arm 2121configured to become coupled to back plate 2110. Auxiliary compressionmechanism 2150 includes a piston that is coupled to arm 2121. The pistoncompresses patient 2182 by compressing the belt. More pistons could beincluded to compress patient 2182 over the belt.

This arrangement could be provided also for the compressions to thechest, or only for the compressions to the chest. In some of theseembodiments, the belt is merely applied with some pressure, but notretracted and released. And, in some of these embodiments, one of thebelt and the piston can be considered to be the main compressionmechanism, and the other can be considered to be the auxiliarymechanism.

In other words, other versions of CPR systems that are usable by arescuer to care for a patient may include a back plate configured toreceive supine a body of the patient, a belt configured to be placedover the supine body, the belt having ends attached to the back plate, amain motor coupled to the back plate, and a first piston coupled to theback plate and configured to be driven by the main motor so as toperform first or main compressions alternating with releases to the bodythrough the belt.

In such versions, the first compressions can be performed on a chest ofthe body or an abdomen of the body. Moreover, such versions can alsoinclude an auxiliary motor coupled to the back plate and configured toretract and release the belt. Or, they can also include an armconfigured to become coupled to the back plate, and in which the firstpiston is coupled to the arm. Or, they can also include a second pistoncoupled to the back plate and configured to perform second compressionsalternating with releases to the body through the belt. In the lattercase, an arm could be further included that is configured to becomecoupled to the back plate, and in which the first piston and the secondpiston are coupled to the arm. The pistons could also have suction cupsto lift against the belt, if elastic enough, and so on. In anotherembodiment, the timing or velocity of each piston in an array of pistonscould be varied to provide variable patterns in active decompression ofthe surface of the chest.

Returning to FIG. 17, regardless of where exactly on the patient's bodythey are performed, the main compressions and the auxiliary compressionscan be coordinated for synergistic effects. Examples are now described.

FIG. 22 shows a time diagram of main compressions 2225, and a timediagram of auxiliary compressions 2227. In some versions at least someof auxiliary compressions 2227 are performed with the same frequency asrespective ones of main compressions 2225. Indeed, in FIG. 22 there is1:1 correspondence of the compressions. The numbers of thesecompressions can be counted within, say, a time interval 2230, fordetermining frequency, etc.

In FIG. 22, at least some of auxiliary compressions 2227 can beperformed in coordination with respective ones of main compressions2225. Indeed, as will be observed at a time TM, auxiliary compressions2227 start when main compressions 2225 reach their peak. Accordingly,auxiliary compressions 2227 lag and are not in phase with maincompressions 2225. This can help in situations where blood is drivenfrom one place, then to another.

FIG. 23 shows a time diagram of main compressions 2325, and a timediagram of auxiliary compressions 2327. As can be seen starting fromtime TS, at least some of auxiliary compressions 2327 are performedconcurrently with respective ones of main compressions 2325. Thishappens because these pulses also have the same duration. Since theystart at the same times, they are also in phase.

Returning to FIG. 17, in some versions, CPR system 1700 further includesa sensor 1746. Sensor 1746 can be configured to sense a parameter ofpatient 1782. In such embodiments, at least some of the maincompressions and the auxiliary compressions are performed at timesdetermined from the sensed parameter of the patient.

Sensor 1746 can be implemented in a number of ways, some of which weredescribed earlier in this document for environmental sensor 446. Forexample, sensor 1746 can include a motion detector that is configured todetect a motion of patient 1782. For another example, sensor 1746 caninclude an electrode that is configured to sense an electrical signal ofthe patient. Two more examples are now described.

FIG. 24 is a diagram of a sensor 2446 being implemented by a ventilator.Indeed, sensor 2446 includes a ventilator configured to be placed over amouth 2483 of patient 2482, and to detect an aspect of a breath ofpatient 2482. In FIG. 24 the patient's eyes 2484 are shown as shut, andthat is how they might be registered by a environmental sensor.

FIG. 25 is a diagram of a sensor 2546 being implemented by aNon-Invasive Blood Pressure (NIBP) cuff. Indeed, sensor 2546 includes anNIBP cuff configured to be placed around an extremity 2585 of thepatient, and to detect a change in the blood pressure of the patient.Extremity 2585 could be an arm, a leg, etc.

Returning to FIG. 17, in some versions, CPR system 1700 further includesa processor (P) 1742. Processor 1742 can be coupled to retentionstructure 1740, for example as described for processor 442. A memory (M)1741 can be provided for processor 1742 with instructions that can beread, etc.

Processor 1742 can be configured to control an operation of maincompression mechanism 1748 or auxiliary compression mechanism 1747, orboth. This controlling may be performed by controlling main motor 1743and/or auxiliary motor 1749. And this controlling may be performed sothat the timing of the main compressions and the auxiliary compressionsis and remains coordinated. In some versions, both main compressionmechanism 1748 and auxiliary compression mechanism 1747 are thuscontrolled, so they are coordinated from the beginning.

In other versions, processor 1742 controls one of the compressionsmechanisms so as to match the compressions by the other, which could behappening independently. For one example, in some versions, processor1742 is configured to control an operation of auxiliary compressionmechanism 1747 such that a timing of at least one of the auxiliarycompressions is coordinated with the performing of at least one of themain compressions or releases from the main compressions, which could behappening independently.

For another example, in some versions, processor 1742 is configured tocontrol an operation of main compression mechanism 1748 such that atiming of at least one of the main compressions is coordinated with theperforming of at least one of the auxiliary compressions or releasesfrom the auxiliary compressions, which could be happening independently.

In some versions, sensor 1746 is configured to sense a parameter ofpatient 1782. In such versions, processor 1742 can be configured tocontrol the operation of main compression mechanism 1748 or auxiliarycompression mechanism 1747 according to the sensed parameter.

In some versions, the parameter of patient 1782 that is sensed by sensor1746 is a sensed timing of the patient's body receiving a compression.For example, the sensed patient parameter can be a sensed timing of thepatient's body receiving a certain one of the main compressions. In suchversions, processor 1742 can be configured to control an operation ofauxiliary compression mechanism 1747 such that a timing of at least oneof the auxiliary compressions is coordinated with respect to the timingof the certain main compression. For another example, the sensed patientparameter can be a sensed timing of the patient's body receiving acertain one of the auxiliary compressions. In such versions, processor1742 can be configured to control an operation of main compressionmechanism 1748 such that a timing of at least one of the maincompressions is coordinated with respect to the sensed timing of thecertain auxiliary compression.

Returning to FIG. 17, embodiments may also benefit from what wasdescribed earlier in this document. For example, the processor maypermit operation in the dynamic mode, and so on.

In yet other embodiments, a single CPR system does not have dualcompression mechanisms in its own right. Rather, it can have a singlemain compression mechanism, for example for the chest, and be extensibleso that it may interoperate with auxiliary devices that provideauxiliary compressions. Such interoperation may be by communicating withsuch other devices, in a wired way with ports or a wireless way withcommunications modules. In addition, such interoperation may enable themain compressions of the CPR system to become coordinated with theauxiliary compressions by enabling cooperation in a master-slaveconfiguration, with either device being able to be the master or theslave, protocols to resolve collisions of contradictory commands, and soon. In such versions, a single one of the interoperating devices mayproject in its user interface status and other information from theother, present options about the other, etc.

FIG. 26 shows a flowchart 2600 for describing methods according toembodiments. According to an operation 2610, a patient's body isretained in a retention structure.

According to another operation 2620, main compressions alternating withreleases may be performed automatically to a chest of the body by a maincompression mechanism and while the body is retained by the retentionstructure. These main compressions can be CPR compressions, such thatthey cause the chest to become compressed by at least 2 cm. The releasesfrom the main compressions may be called main releases.

According to another operation 2630, auxiliary compressions alternatingwith releases may be performed automatically to body by an auxiliarycompression mechanism and while the body is retained by the retentionstructure. Operation 2630 may take place concurrently with operation2620. The releases from the auxiliary compressions may be calledauxiliary releases. Operation 2630 may be performed to the chest, to theabdomen, an extremity, etc.

If operation 2630 is performed to the abdomen then, according toanother, optional operation 2640, the abdomen may be lifted during theauxiliary releases. Such lifting may be above the normal at the timeresting vertical level of the abdomen.

According to another, optional operation 2650, a user input may bereceived from a user interface. According to another, optional operation2660, it is inquired whether the performance of the compressions needsto be revised in view of operation 2650. If yes, execution may return tooperation 2620, or perhaps to 2630, with the compression parametersrevised.

If not, then according to another, optional operation 2670, a patientparameter may be sensed. According to another, optional operation 2680,it is inquired whether the performance of the compressions needs to berevised in view of operation 2650. If yes, execution may return tooperation 2620, or perhaps to 2630, with the compression parametersrevised. If not, execution may return to operation 2620 with thecompression parameters not revised.

Due to either operation 2660 or 2680, the compression parameters may berevised. Such a parameter can be the timing, the frequency (also knownas rate and repetition rate), another the duty ratio, and so on. In someversions, an operation of the auxiliary compression mechanism iscontrolled such that a timing of at least one of the auxiliarycompressions becomes coordinated with the performing of at least one ofthe main compressions or releases from the main compressions. In someversions, an operation of the main compression mechanism is controlledsuch that a timing of at least one of the main compressions becomescoordinated with the performing of at least one of the auxiliarycompressions or releases from the auxiliary compressions.

In the methods described above, each operation can be performed as anaffirmative step of doing, or causing to happen, what is written thatcan take place. Such doing or causing to happen can be by the wholesystem or device, or just one or more components of it. It will berecognized that the methods and the operations may be implemented in anumber of ways, including using systems, devices and implementationsdescribed above. In addition, the order of operations is not constrainedto what is shown, and different orders may be possible according todifferent embodiments. Examples of such alternate orderings may includeoverlapping, interleaved, interrupted, reordered, incremental,preparatory, supplemental, simultaneous, reverse, or other variantorderings, unless context dictates otherwise. Moreover, in certainembodiments, new operations may be added, or individual operations maybe modified or deleted. The added operations can be, for example, fromwhat is mentioned while primarily describing a different system,apparatus, device or method.

A person skilled in the art will be able to practice the presentinvention in view of this description, which is to be taken as a whole.Details have been included to provide a thorough understanding. In otherinstances, well-known aspects have not been described, in order to notobscure unnecessarily this description. Plus, any reference to any priorart in this description is not, and should not be taken as, anacknowledgement or any form of suggestion that such prior art formsparts of the common general knowledge in any country or any art.

This description includes one or more examples, but this fact does notlimit how the invention may be practiced. Indeed, examples, instances,versions or embodiments of the invention may be practiced according towhat is described, or yet differently, and also in conjunction withother present or future technologies. Other such embodiments includecombinations and sub-combinations of features described herein,including for example, embodiments that are equivalent to the following:providing or applying a feature in a different order than in a describedembodiment; extracting an individual feature from one embodiment andinserting such feature into another embodiment; removing one or morefeatures from an embodiment; or both removing a feature from anembodiment and adding a feature extracted from another embodiment, whileproviding the features incorporated in such combinations andsub-combinations.

In general, the present disclosure reflects preferred embodiments of theinvention. The attentive reader will note, however, that some aspects ofthe disclosed embodiments extend beyond the scope of the claims. To therespect that the disclosed embodiments indeed extend beyond the scope ofthe claims, the disclosed embodiments are to be considered supplementarybackground information and do not constitute definitions of the claimedinvention.

In this document, the phrases “constructed to” and/or “configured to”denote one or more actual states of construction and/or configurationthat is fundamentally tied to physical characteristics of the element orfeature preceding these phrases and, as such, reach well beyond merelydescribing an intended use. Any such elements or features can beimplemented in a number of ways, as will be apparent to a person skilledin the art after reviewing the present disclosure, beyond any examplesshown in this document.

Any and all parent, grandparent, great-grandparent, etc. patentapplications, whether mentioned in this document or in an ApplicationData Sheet (“ADS”) of this patent application, are hereby incorporatedby reference herein as originally disclosed, including any priorityclaims made in those applications and any material incorporated byreference, to the extent such subject matter is not inconsistentherewith.

In this description a single reference numeral may be used consistentlyto denote a single item, aspect, component, or process. Moreover, afurther effort may have been made in the drafting of this description touse similar though not identical reference numerals to denote otherversions or embodiments of an item, aspect, component or process thatare identical or at least similar or related. Where made, such a furthereffort was not required, but was nevertheless made gratuitously so as toaccelerate comprehension by the reader. Even where made in thisdocument, such a further effort might not have been made completelyconsistently for all of the versions or embodiments that are madepossible by this description. Accordingly, the description controls indefining an item, aspect, component or process, rather than itsreference numeral. Any similarity in reference numerals may be used toinfer a similarity in the text, but not to confuse aspects where thetext or other context indicates otherwise.

This disclosure, which may be referenced elsewhere as 3198, is meant tobe illustrative and not limiting on the scope of the following claims.

The claims of this document define certain combinations andsubcombinations of elements, features and steps or operations, which areregarded as novel and non-obvious. Additional claims for other suchcombinations and subcombinations may be presented in this or a relateddocument. These claims are intended to encompass within their scope allchanges and modifications that are within the true spirit and scope ofthe subject matter described herein. The terms used herein, including inthe claims, are generally intended as “open” terms. For example, theterm “including” should be interpreted as “including but not limitedto,” the term “having” should be interpreted as “having at least,” etc.If a specific number is ascribed to a claim recitation, this number is aminimum but not a maximum unless stated otherwise. For example, where aclaim recites “a” component or “an” item, it means that it can have oneor more of this component or item.

What is claimed is:
 1. A cardiopulmonary resuscitation (CPR) system,comprising: a first compression mechanism configured to compress a bodyof a patient at a first location, the first location being a chest ofthe patient; a second compression mechanism configured compress the bodyof the patient at a second location, the second location different fromthe first location; and a processor in operative communication with thefirst compression mechanism and the second compression mechanism, theprocessor configured to coordinate driving the first compressionmechanism and the second compression mechanism.
 2. The CPR system ofclaim 1, wherein the processor is further configured to drive the firstcompression mechanism and the second compression mechanism at the samefrequency.
 3. The CPR system of claim
 2. wherein the processor isfurther configured to drive the first compression mechanism and thesecond compression mechanism out of phase.
 4. The CPR system of claim 1,wherein the processor is further configured to the drive firstcompression mechanism and the second compression mechanism concurrently.5. The CPR system of claim 1, further comprising a sensor configured tosense a parameter of a patient, wherein the processor is furtherconfigured to drive one of the first compression mechanism or the secondcompression mechanism based on the sensed parameter.
 6. The CPR systemof claim 1, wherein the second compression mechanism is a belt drivencompression mechanism.
 7. The CPR system of claim 1, wherein the secondcompression mechanism is a piston driven compression mechanism.
 8. TheCPR system of claim 1, wherein the first compression mechanism is one ofa belt driven compression mechanism or a piston compression mechanismand the second compression mechanism is the other of the belt drivencompression mechanism or the piston compression mechanism.
 9. The CPRsystem of claim 1, further comprising a retention structure structuredto receive the patient supine.
 10. The CPR system of claim 1, whereinthe second location is an abdomen of the patient.
 11. A method forperforming cardiopulmonary resuscitation on a patient, comprising:compressing by a first compression mechanism a body of a patient at afirst location, the first location is a chest of the patient;compressing by a second compression mechanism the body of the patient ata second location, different from the first location; and coordinatingdriving the first compression mechanism and the second compressionmechanism to compress the body of the patient.
 12. The method of claim10, wherein coordinating driving the first compression mechanism and thesecond compression mechanism includes driving the first compressionmechanism and the second compression mechanism at the same frequency.13. The method of claim 12, wherein coordinating driving the firstcompression mechanism and the second compression mechanism includesdriving the first compression mechanism and the second compressionmechanism out of phase.
 14. The method of claim 11, wherein coordinatingdriving the first compression mechanism and the second compressionmechanism includes driving first compression mechanism and the secondcompression mechanism concurrently.
 15. The method of claim 11, furthercomprising sensing a parameter of a patient and coordinating driving thefirst compression mechanism and the second compression mechanismincludes based on the sensed parameter.
 16. The method of claim 11,wherein the second compression mechanism is a belt driven compressionmechanism.
 17. The method of claim 11, wherein the second compressionmechanism is a piston driven compression mechanism.
 18. The method ofclaim 11, wherein the first compression mechanism is one of a beltdriven compression mechanism or a piston compression mechanism and thesecond compression mechanism is the other of the belt driven compressionmechanism or the piston compression mechanism.
 19. The method of claim11, further comprising receiving the patient supine at a retentionstructure.
 20. The method of claim 11, wherein the second location is anabdomen of the patient.